In order to produce an acceptable impact absorbing article, for example, a gym mat, a foam material must have the proper shock absorbing and safety features and be soft enough to permit the mat to be rolled for shipping and storage purposes. Presently, polyvinyl chloride foams have been provided with a flexible vinyl protective finish of from 10 - 25 mils. thick.
A polyethylene crosslinked closed cell flexible foam meets the basic requirement for an impact absorbing material and offers a number of important advantages (in addition to cost considerations) over a PVC closed cell foam, e.g. less shrinkage after coating (1% vs. - 15% for PVC foam), lighter in weight (approximately 30% less), low temperature flexibility, ease of heat sealing for bonding purposes. It will be appreciated that while either foam without such a protective film met the requirements of a gym mat, that such a foam is rather weak and will be readily destroyed in such use.
To date, the major drawback to the use on Gym Mat applications of a polyolefinic-containing foam has been the inability to obtain adhesion of a protective vinyl film to the polyolefinic foam so that the weakest point of the composite upon destruction is foam failure. In U.S. Pat. No. 3,816,234 to Winfield there is disclosed an energy absorbing laminate comprised of a plurality of layers requiring many processing steps.